Optical techniques are exploited in a very wide range of measurement technologies. An important factor in any measurement is the sensitivity to small changes in the physical property being measured. Therefore an invention which can enhance the sensitivity of several types of optical measurement has many potential applications.
Acousto-optic devices rely on the interaction of optical and acoustic waves within certain transparent materials. They are extensively used in optical systems to control the intensity, wavelength and beam direction of light. The two types of acousto-optic devices which are used in this invention are acousto-optical deflectors and acousto-optic tunable filters. As their names imply an acousto-optic deflector will electronically control the angle through which a light beam is deflected on traversing the device and an acousto-optic tunable filter will control the wavelength of light transmitted by the device. The important features of these devices are their very fast scan rate and continuous scan range. In both these respects acousto-optic devices are superior to their electromechanical equivalents, although more limited in angle and wavelength scan range.